According to findings published in the November 2012 issue of Annals of Neurology, a new gene variant has been identified that predicts not only if you’re a morning or night person, but also what time of day you’re likely to die.
Harvard Medical School News reports,
“The internal ‘biological clock’ regulates many aspects of human biology and behavior, such as preferred sleep times, times of peak cognitive performance, and the timing of many physiological processes. It also influences the timing of acute medical events like stroke and heart attack,” says first author Andrew Lim, who conducted the work as a postdoctoral fellow in the Department of Neurology at Beth Israel Deaconess Medical Center.
Lim’s research, which stemmed from an earlier study on sleeping problems and aging led by Dana Alliance member Clifford Saper, M.D., Ph.D., and funded by the Dana Foundation, compared wake-sleep behavior of healthy 65 year olds to their genotypes.
According to Harvard Medical School News,
[Lim and his colleagues] soon discovered a single nucleotide near a gene called “Period 1” that varied between two groups that differed in their wake-sleep behavior. At this particular site in the genome, 60 percent of individuals have the nucleotide base adenine (A) and 40 percent have the nucleotide base guanine (G). Because we have two sets of chromosomes, in any given individual, there’s about a 36 percent chance of having two As, a 16 percent chance of having two Gs, and a 48 percent chance of having a mixture of A and G at this site…
When the investigators went back and looked at the people in the study (many of whom had enrolled more than 15 years ago at age 65) who had died, they found that this same genotype predicted six hours of the variation in the time of death: those with the AA or AG genotype died just before 11 a.m., like most of the population, but those with the GG genotype on average died at just before 6 p.m.
The investigators hope that this research will eventually help people to better plan their daily schedules based on their biological clocks, and also inform decisions about when to take certain medications.
--Ann L. Whitman